Liquid-feeding attachment for dental engines



July 20 1926. 1,592,854

F. .1. HOFSCHNEIDER LIQUID FEEDING ATTACHMENT FOR DENTAL ENGINES Filed March 2, 1925 2 Shegts-Sheet 1 Patented July 20, 1926.

UNITED STATES PATENT OFFICE.

FREDEBIC J. HOFSCHNEIDER, OF ROCHESTER, NEW YORK;

LIQUID-FEEDING ATTACHMENT FOR DENTAL ENGINES.

Application filed March 2, 1925., Serial No. 12,580.

Another object of the improvement is to.

afford means for effecting the results stated, without using any electrical instrumentality between the motor and the liquid governing valve, but depending entirely upon mechanical devices for efl'ecting the desired movement of the Valve. Y

An additional purpose of the improvement is to afi'ord a construction with few "'andsimple parts and which can be manufactured and sold at a low cost. I

To these and otherends, the invention comprises the "structure that will appear clearly from the following description, when read in conjunction .with the accompanying drawings, the novel features being pointed out in the claims :at the end of the specification.

In the drawings Figure 1 is a side elevation of a' conventional form of dental engine equipped with a preferred embodimentof my invention;

Figure2 is a partial plan view of the same;

Figure 3 is a sectional View on the line 3-3 of Figure 1, showing the liquid tank in side elevation;

Figure 4 is a sectionalview of the liquid tank and valve controlling parts, with the valve in closed position;

Figure 5 is a similar view of the valve in open position;

Figure 6 is a horizontal sectional View on line 66 of Figure 4;

Figure 7 is a similar View illustrating the position of the parts when turning in the opposite direction, and

Figure 8 is a sectional view of a modified arrangement of parts embodying the invention.

Fig. 9 is a plan View of the cam disk and 021111.

The device is applicable in a. variety ways to any motor driven dental engine, and depends for its operation entirely upon mechanical parts, independently of any electrical control, and actuated by the turning'movement of the motor or someelement connected therewith. The particular forms illustrated are intended merely as examples of many possible arrangements that might be devised. In the mechanism of Figures 1 to '7, l designates the usual swinging bracket of a dental engine, 2 is the hand piece, 3 is a grinding tool, and 4; is an electric motor opcrating the grinding tool through a belt or cable 5.

. Liquid is fed to the grinding wheel from a nozzle 6 which is supplied through a tube 7 connecting with the tank 8 suitably mounted upon the bracket 1, and from which the liquid flows by gravity through the tube 7 and nozzle 6.

The How of liquid from the tank 8 is governed by a valve 10 which engages a seat 11 and is held normally in closed position by a spring 12. 13 is a rod having connection with the upper end of the valve rod 10,

while 14L is .a nut or head mounted upon the upper end of the rod 13 resting upon a collar 15. In order to open the valve 10 entirely from the movement of some motor driven part, I provide the following construction.

The rod 13 passes through an arbor 16 that is fixedly mounted on the upper end of the tank 8. Journ-alled on said arbor is a pulley 17 which carries a ball governor consisting of arms 18 weighted at 19 and slotted at 20 for engagement with the pivotal supports 21. The arms 18 are provided with inwardly projecting extensions 22 which engage under the aforementioned collar 15 and act to elevate the same when the governor arms are thrown horizontally, as in Figure 5. The pulley 17 is positioned so as to permit the belt or cable 5 to pass in engage ment therewith, as shown in Figure 2, so as to rotate the pulley when the motor is operating, Thus, upon operation of the motor in either direction, the pulley 17 is rotated by the belt, and through the governor arms 18, elevates the collar 15 and connecting rod 13 and opens the valve against the act-ion of spring 12, which automatically reseats the valve when the motor stops by overcoming the action of governor arms 18 and. serene ing them to normal position, shown in Figure 4.

In some instances, it is desirable to permit a flow of liquid only when the motor is running in one direction, and to not open the liquid supply when the motor is operating in a reverse direction. I11 order to accomplish this, I may employ a supplemental pulley which is journalled on the arbor 16 and associated with the pulley 17 so as to operate it only when turning in one direction. To this end, the pulley 25 carries a centrifugal pawl 26 arranged to cooperate with a shoulder 27 on pulley 17, as shown in Figures 6 and 7. When the belt or cable 5 is engaged by pulley 25, and the pulley 25 is operating in the direction shown in Figure 6, no movement of pulley 17 occurs, but when pulley 25 turns in the opposite direction, the centrifugal pawl 26 is thrown outwardly, as shown in Figure 7, until it rests against the stop 28, and then upon engaging shoulder 27, it turns the pulley 17 and with it the ball governor, causing the valve 10 to be opened, as already described.

Figure 8 shows a modified arrangement for accomplishing the same result, and consisting of pulley 31 adapted to receive the belt or cable and held frictionally against a cam disk 32 by a spring 33 located between the pulley 31 and the fixed collar 34. The cam disk 32 has a cam surface 35 cooperating with a pin or projection 36 on the rod 37 which connects with the valve. Upon starting the motor, the pulley 31 is rotated, and by frictional engagement with disk 32, turns the latter far enough to cause the cam surface 35 to elevate pin 36 and rod 37, thereby opening the valve. Upon stopping of the motor and pulley 31, the spring 12 will return the valve and rod 37 to normal position.

Other changes in the arrangement or details of the structure shown can be made without departing from the principal features of the invention, and this application is intended to cover any such departures as the improvement or the scope of the following claims.

I claim 1. In adental engine, the combination with a tool, a liquid supply for the tool, a motor for operating the tool, and a valve governing the liquid supply, of means operatively connected to a motor-rotated part acting to open the valve when the motor is running, the valve being automatically closed when the motor stops.

2. In a dental engine, the combination with a tool, a liquid supply for the tool, a motor for operating the tool, and a valve governing the liquid supply, of speed-controlled means operated by the motor and acting to open the valve when the motor is running, the valve being automatically closed when the motor is idle.

3. In a dental engine, the combination with a tool, a liquid supply for the tool, a motor for operating the tool, a valve governing the liquid supply, and a cable connecting the motor and tool for operating the latter, of means operated by said cable for opening the valve when the motor is run ning, the valve being automatically closed when the motor is idle.

1. In a dental engine, the combination with a tool, a liquid supply for the tool, a motor foroperating the tool, a valve governing the liquid supply, and a cable connecting the motor and tool for operating the latter, of'speed-controlled means operated by the cable for openingthe valve when the motor is running, the valve being automatically closed when the motor is idle.

5. In a dental engine, the combination with a tool, a liquid supply for the tool, a motor for operating the tool, a valve governing the liquid supply, and a cable connecting the motor and tool for operating the latter, of a speed governor operated by said cable and operatively connected to the valve for opening it.

In witness whereof, I have hereunto signed my name.

FREDERIC J. HOFSCHNEIDER. 

